CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no . 102020000026155 filed on November 3 , 2020 , the entire disclosure of which is incorporated herein by reference .

TECHNICAL FIELD

The present invention relates to a method and to a unit to bend a straw .

PRIOR ART

Straws are known which provide a corrugated intermediate portion in order to allow the bending of the straw so as to assume the most suitable shape in use to satis fy the user .

For some applications , a straw is packaged individually (namely, it is inserted singly into its own wrap) after being bent in a "U"-shape (namely, by 180 ° ) at the corrugated intermediate portion ( the purpose of bending in a "U"-shape is to reduce the overall dimensions of the straw) ; typically, it is required to individually package the "U"-bent straws when the straws have to be fixed ( glued) to the back wall of a beverage container .

The Patent application CN111055486A describes a high-speed straw bending machine .

DESCRIPTION OF THE INVENTION

The obj ect of the present invention is to provide a method and a unit to bend a straw that allow operating at a high processing speed (measured by the number of pieces produced per unit of time ) while , at the same time , maintaining a high production quality (namely, without damaging the straw during bending) . According to the present invention, a method and a unit to bend a straw are provided, according to what is established in the attached claims .

The claims describe preferred embodiments of the present invention forming an integral part of the present description .

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings , which illustrate a non-limiting embodiment thereof , wherein :

• Figure 1 is a perspective view of a straw applied to a beverage package ;

• Figure 2 is a view on an enlarged scale of the straw of Figure 1 ;

• Figure 3 is a schematic and front view of a packing machine which bends and wraps the straw of Figure 1 ;

• Figure 4 shows a series of schematic and cross-sectional views of a seat of a bending drum of the packing machine of Figure 3 which illustrate the sequence for bending the straw of Figure 1 ;

• Figure 5 is a view on an enlarged scale of Figure 41 with the addition of a plan view of the seat of the bending drum;

• Figure 6 is a view on an enlarged scale of Figure 4e ;

• Figure 7 is a perspective view of the bending drum of Figures 4 ; and

• Figures 8 , 9 and 10 are di f ferent views of two bending elements and of an accompanying element coupled to the bending drum of Figures 4 .

PREFERRED EMBODIMENTS OF THE INVENTION

In Figure 1 , number 1 denotes as a whole a straw (made of paper or plastic ) which is applied to the back of a beverage package . The straw 1 has a flat end 2 (which is grasped by the user ' s lips ) and a pointed end 3 ( to more ef fectively break through the cap that seals a dispensing opening of the package ) .

In addition, the straw 1 has a corrugated intermediate portion 4 at which the straw 1 can be easily bent and without breaking (namely, in an elastic manner ) so as to assume in use the most suitable shape to satis fy the user .

The straw 1 is packaged individually (namely, it has been inserted singly in its own wrap 5 not illustrated in Figure 1 and illustrated in Figure 2 ) after being bent in a "U"-shape (namely, by 180 ° ) at the corrugated intermediate portion 4 ( the purpose of the "U"-bending is to reduce the overall dimensions of the straw 1 in order to remain within the overall dimensions of the back wall of the package to which the straw 1 is applied) .

In Figure 3 , number 6 denotes as a whole a packing machine which receives the straws 1 from a manufacturing machine (not illustrated) , corrugates the straws 1 , bends the straws 1 in a "U"-shape , and inserts the straws 1 in corresponding wraps 5 .

The packing machine 6 comprises a hopper 7 which is designed to contain a mass of straws 1 coming from the manufacturing machine and which move progres sively downwards by gravity, namely, towards the bottom of the hopper 7 . As an alternative to the hopper 7 , the packing machine 6 could provide any type of buf fer or collector for a mass of straws . As a further alternative , the packing machine 6 could receive the straws in an orderly manner (namely, not collected in a mass ) , for example directly from the manufacturing machine .

A pick-up conveyor 8 is arranged on the bottom o f the hopper 7 , the conveyor picks up a succession of straws 1 by feeding the latter crosswise (namely, perpendicularly to a longitudinal axis of the straws 1 ) ; according to a preferred embodiment , the pick-up conveyor 8 is a conveyor belt , namely, it comprises a flexible belt which is closed in a loop around two end pulleys and supports a plurality of suction seats , each designed to house a corresponding straw 1 . According to embodiments not illustrated, the pick-up conveyor 8 could comprise one or more conveying drums ; at least one of these conveying drums could be a conical drum .

The packing machine 6 comprises a corrugator drum 9 which is mounted so as to rotate around a rotation axis 10 , has a plurality of suction seats each designed to house a corresponding straw 1 , and receives the straws 1 directly from the pick-up conveyor 8 . A corrugator device 11 is arranged along the periphery of the corrugator drum 9 , which corrugates the straws 1 , namely, creates the corrugated intermediate portion 4 of each straw 1 .

According to an embodiment not illustrated, the packing machine 6 could receive already corrugated straws 1 ; in this case , the packing machine 6 does not comprise any corrugator drum 9 .

The packing machine 6 comprises a bending drum 12 which is mounted so as to rotate around a rotation axis 13 (parallel to the rotation axis 10 ) , has a plural ity of suction seats 14 ( illustrated in Figures 4-7 ) each designed to house a corresponding straw 1 , and receives the straws 1 directly from the corrugator drum 9 . Two bending elements 15 and 16 and an accompanying element 17 (better illustrated in Figures 8 , 9 and 10 ) are arranged around the rotation axis 13 in a fixed position (namely, integral with a frame of the packing machine 6 and, therefore , motionless ) , which are coupled to the bending drum 12 and interact with the straws 1 carried by the suction seats 14 for bending the straws 1 in a "U"-shape .

The packing machine 6 comprises a wrapping drum 18 which is mounted so as to rotate around a rotation axis 19 (parallel to the rotation axis 13 ) , has a plurality of suction seats 20 each designed to house a wrapping sheet and a straw 1 bent in a "U"-shape . Each suction seat 20 of the wrapping drum 18 receives a strip 21 of wrapping material which is bent in a "U"-shape inside the suction seat 20 (where it is held by suction) and then receives a straw 1 bent in a "U"-shape (which is arranged inside the strip 21 of wrapping material bent in a "U"-shape ) subsequently and directly from the bending drum 12 . In particular , an inserter drum 22 is provided which inserts , in each suction seat 20 of the wrapping drum 18 , a portion of the strip 21 of wrapping material that is bent in a "U"-shape inside the suction seat 20 . An applicator drum 23 is coupled to the wrapping drum 18 , which applies , to each wrapping sheet bent in a "U"-shape and containing a straw 1 bent in a "U"-shape , a corresponding lid ( defined by a further strip of wrapping material , thus completing the formation of a wrap 5 ) which is fixed by heat sealing or by gluing ( thanks to the presence of glue which is previously applied to the strip 21 of wrapping material or to the lid) .

The packing machine 6 comprises an outlet conveyor 24 which receives a continuous strip of wraps 5 containing respective straws 1 from the wrapping drum 18 and feeds the wraps 5 towards an outlet of the packing machine 6 .

According to a particular embodiment , the outlet conveyor 24 is a conveyor belt , namely, it comprises a flexible belt which is closed in a loop around two end pulleys and supports a plurality of suction seats each designed to house a corresponding wrap 5 . According to a preferred embodiment , the applicator drum 23 is arranged at the exchange station between the wrapping drum 18 and the outlet conveyor 24 .

As illustrated in Figures 7- 10 , the bending element 15 is shaped like an arc of a circle , is arranged in a fixed position around the rotation axis 13 and has a radial position which is variable so that the rotation of the bending drum 12 causes a progressive relative radial movement between the bending element 15 and the seats 14 ; namely, each seat 14 rotating around the rotation axis 13 together with the rest of the bending drum 12 , "percei ves" a radial movement of the bending element 15 due to the variation of the radial position of the bending element 15 along its circumferential extension . It is important to note that the variable radial position of the bending element 15 refers to the active side of the bending element 15 , namely, the side of the bending element 15 that comes into contact with the straws 1 carried by the seats 14 .

According to what is illustrated in Figures 7- 10 , the bending element 16 is shaped like an arc of a circle , is arranged in a fixed position around the rotation axis 13 and has an axial position which is variable so that the rotation of the bending drum 12 causes a relative progressive axial movement between the bending element 16 and the seats 14 ; namely, each seat 14 rotating around the rotation axis 13 together with the rest of the bending drum 12 , "percei ves" an axial movement of the bending element 16 due to the variation of the axial position of the bending element 16 along its circumferential extension . It is important to note that the variable axial position of the bending element 16 refers to the active side of the bending element 16 , namely, the side of the bending element 16 that comes into contact with the straws 1 carried by the seats 14 .

According to what is illustrated in Figures 8- 10 , the accompanying element 17 is ring-shaped (but alternatively it could be shaped only like an arc of a circle since a part of the accompanying element 17 has no active function, that is , it never makes contact with the straws 1 carried by the seats 14 ) , is arranged in a fixed position around the rotation axis 13 and has a radial position which is variable so that the rotation of the bending drum 12 causes a relative progressive radial movement between the accompanying element 17 and the seats 14 ; namely, each seat 14 rotating around the rotation axis 13 together with the rest of the bending drum 12 , "percei ves" a radial movement of the accompanying element 17 due to the variation of the radial position of the accompanying element 17 along its circumferential extension . It is important to note that the variable radial position of the accompanying element 17 refers to the active side of the accompanying element 17 , namely, the side of the accompanying element 17 that comes into contact with the straws 1 carried by the seats 14 .

According to what is illustrated in Figures 5 and 6 , the bending drum 12 has a central circumferential sl it 25 ( i . e . , which develops for 360 ° around the rotation axis 13 ) , which is oriented radially and is configured to contain the accompanying element 17 ; namely, the accompanying element 17 is arranged inside the circumferential slit 25 of the bending drum 12 .

According to what is illustrated in Figures 5 and 6 , each seat 14 comprises two suction walls 26 (namely, provided with small holes that can be connected when necessary to a suction source ) which are axially oriented, are arranged at a certain distance from one another, and are designed to receive and hold two opposite ends of a straight straw 1 (namely, without bends and, therefore , still having a completely rectilinear shape ) . According to what is illustrated in Figure 7 , the two suction walls 26 have a semi-circle shape to reproduce in negative the shape of a straw 1 and, therefore , also to laterally contain a straw 1 .

According to what is illustrated in Figures 5 and 6 , at each seat 14 the bending drum 12 is provided with a cavity 27 (namely, a hole ) which is radially arranged further inwards than the seat 14 , namely, it extends starting from the seat 14 towards the centre (namely, the rotation axis 13 ) . In particular, the circumferential slit 25 , which contains the accompanying element 17 , opens into the cavity 27 , namely the circumferential slit 25 originates from a bottom of each cavity 27 . Each cavity 27 has an outer portion 28 delimited on one side by a wall 29 radially arranged and, on the opposite side , by a wall 30 that forms an acute angle ( of the order of about 60 ° ) with the wall 29 ( and remains at a certain distance from the wall 29 ) ; furthermore , each cavity 27 has an inner portion 31 which is radially arranged further inwards than the outer portion 28 and is delimited on one side by the wall 29 (namely, by the same radially arranged wall 29 , which also delimits the outer portion 28 ) and on the opposite side by a wall 32 that is connected to the wall 30 (namely, it forms a j oining corner with the wall 30 ) and is arranged radially and, therefore , parallel to the wall 29 .

The methods for bending a straw 1 in a "U"-shape in the bending drum 12 are described in the following and with particular reference to what is illustrated in Figures 4 .

Initially, and as illustrated in Figure 4a , the straw 1 is fed straight to the seat 14 and then the two opposite ends of the straw 1 engage the two walls 26 of the seat 14 (which initially hold the straw 1 by suction) .

Subsequently and as illustrated in Figures 4b-4e , the straw 1 is progressively pushed into the cavity 27 by means of the action of the bending element 15 which moves radially relative to the seat 14 for at least partially bending the straw 1 in a "U"-shape against ( at least ) the wall 29 of the cavity 27 ; the introduction of the straw 1 into the cavity 27 is accompanied by means of the action of the accompanying element 17 , which is arranged on the opposite side of the straw 1 relative to the bending element 15 and moves radially relative to the seat 14 (namely, the bending element 15 and the accompanying element 17 "pinch" the straw 1 between one another to guide the radial movement of the straw 1 on both sides and, therefore , control the exact radial position of the straw 1 at all times ) .

According to a preferred embodiment illustrated in Figure 4e ( and also in Figure 6 which reproduces Figure 4e on an enlarged scale ) , the bending element 15 pushes the straw 1 inside the inner portion 31 of the cavity 27 until it reaches a bottom of the inner portion 31 , namely, until the straw 1 is in contact with the bottom of the inner portion 31 .

According to what is illustrated in Figure 4 f , once the straw 1 is at least partially bent in a "U"-shape inside the inner portion 31 of the cavity 27 , the at least partially "U"-bent straw 1 is subsequently extracted from the inner portion 31 of the cavity 27 by pushing the straw 1 radially outwards by means of the action of the accompanying element 17 (which is arranged on the opposite side of the straw 1 relative to the bending element 15 and moves radially relative to the seat 14 ) .

As illustrated in Figures 4g and 4h, simultaneously with the radial thrust towards the outside of the straw 1 at least partially bent in a "U"-shape , operated by the accompanying element 17 , the bending element 16 also intervenes by starting to push the straw 1 at least partially bent in a "U"-shape and extracted from the inner portion 31 , against the wall 30 of the outer portion 28 of the cavity 27 . According to a preferred embodiment illustrated in Figures 4g and 4h, the bending element 16 comprises a holding tooth 33 which engages the end 2 of the straw 1 so as to prevent the straw 1 from being ( accidentally and obviously in a completely undesired manner ) elasticity " shot" out of the cavity 25 while being bent against the wall 30 of the outer portion 28 . According to what is illustrated in Figure 4 i , by means of the action of the bending element 16 the bending of the straw 1 in a "U"- shape is completed by pushing the at least partially "U"-bent straw 1 against the wall 30 of the outer portion 28 .

Finally, and as illustrated in Figure 41 , the straw 1 completely bent in a "U" -shape is rotated by 90 ° by means of the action of the bending element 16 so as to be arranged "fla t" ( instead of " standing uprigh t" ) , consequently coming out of the cavity 27 ( as better illustrated in Figure 5 , which reproduces Figure 41 on an enlarged scale ) . Preferably, the accompanying element 17 pushes the straw 1 towards the bending element 16 until the rotation by 90 ° of the completely "U"- bent straw 1 , keeping the straw 1 clamped between the accompanying element 17 and the bending element 16 .

Preferably, the cavity 27 has a circumferential width which is only slightly larger than the thickness of the straw 1 ( as illustrated in Figure 5 ) so as to be able to contain the partially or completely "U"-bent straw 1 only when the partially or completely "U"-bent straw 1 is arranged " standing uprigh t" (namely, it is radially oriented) . Beside the cavity 27 a housing 34 is obtained, ( illustrated in Figure 5 ) , which is shaped so as to contain the completely "U"-bent straw 1 after its rotation by 90 ° and, therefore , after its extraction from the cavity 27 ; namely, the rotation by 90 ° causes the extraction of the completely "U"-bent straw 1 from the cavity 27 and the subsequent insertion of the completely "U"-bent straw 1 into the housing 34 .

According to a possible embodiment illustrated in Figure 5 , the wall 29 of each cavity 27 is provided with a pneumatic device 35 which can be operated to generate a blast of compressed air which pushes the straw 1 towards the wall 30 of the outer portion 28 ; the function of the pneumatic device 35 (which is activated only when the at least partially "U"-bent straw is extracted from the inner portion 31 of the cavity 27 ) is to prevent a straw 1 from remaining too close to the wall 29 and, therefore , not being able to be rotated correctly by 90 ° in order to be extracted from cavity 27 and inserted into the housing 34 .

According to a preferred embodiment , the packing machine 6 operates on a double line , namely, it processes two straws 1 at a time arranged end to end (namely, axially aligned with one another ) . In other words , the pick-up conveyor 8 has a series of pairs of suction seats ( axially aligned with one another ) to pick-up two straws 1 at a time from the outlet mouth of the hopper 7 and the corrugator drum 9 has a series of pairs of suction seats ( axially aligned with one another ) which simultaneously receive two straws 1 from the pick-up conveyor 8 , simultaneously corrugate two straws 1 together with the corrugator device 11 , and simultaneously release two straws 1 to the bending drum 12 . According to a further alternative , the pick-up conveyor 8 has a series of suction seats having a length double the length of a straw to pick-up a semi- finished product having a length double that of a straw from the outlet mouth of the hopper 7 . In this case , a cutting member can be arranged at the pick-up conveyor 8 to cut , with a straight or inclined cut , the semi- finished product into two straws . These two straws will then be trans ferred to the corrugator drum 9 as described above .

In turn, the bending drum 12 has a series of pairs of suction seats 14 ( axially aligned with one another ) which simultaneously receive two straws 1 from the corrugator drum 9 , simultaneously bend two straws 1 ( operating with two respective pairs of elements 15 , 16 and 17 ) , and simultaneously release two straws 1 to the wrapping drum 18 . In turn, the wrapping drum 18 has a series of pairs of suction seats 20 ( axially aligned with one another ) which simultaneously receive two straws 1 from the bending drum 12 , simultaneously produce two wraps 5 ( operating with a strip 21 of wrapping material having double width) , and simultaneously trans fer two wraps 5 to the outlet conveyor 24 . In turn, the outlet conveyor 24 has a series of pairs of suction seats ( axially aligned with one another ) which simultaneously receive two wraps 5 from the wrapping drum 18 .

According to a di f ferent embodiment , the packing machine 6 operates on a single line , namely, it processes only one straw 1 at a time .

According to a further embodiment , the packing machine 6 operates on a triple or quadruple line , namely, it processes three or four straws 1 at a time arranged end to end (namely, axially aligned with one another ) .

The embodiments described herein can be combined with each other without thereby departing from the scope of the present invention .

The bending unit described above ( essentially formed by the bending drum 12 and by the elements 15 , 16 and 17 ) has numerous advantages .

Firstly, the bending unit described above allows to operate at a high processing speed (measured as the number of pieces produced in a unit of time ) while , at the same time , maintaining a high production quality (namely, without damaging the straws 1 during bending) .

Furthermore , the bending unit described above is simple , inexpensive and compact to implement , as it does not have any moving parts but only elements 15, 16 and 17 , which are suitably shaped and are arranged in a fixed position around the rotation axis 13.